Baltimore developer Ronald H. Lipscomb apologized in court Thursday for violating campaign finance rules and accepted a sentence of three years of unsupervised probation, 100 hours of community service and a $25,000 fine imposed by Circuit Judge Dennis M. Sweeney.

"I have no one else to blame but myself," Lipscomb said at a sentencing hearing for his role in the City Hall corruption scandal. "If I had not made some stupid and selfish decisions, I would not be here today."

Sweeney also barred Lipscomb from donating to any city political candidates or attending campaign events during the probation period. Lipscomb pledged to continue cooperating with the state prosecutor's investigation of City Hall practices, including testifying if needed at the trial next month of his former girlfriend, Baltimore Mayor Sheila Dixon.

"There is a cozy relationship between developers and politicians in this town," State Prosecutor Robert A. Rohrbaugh said after the hearing. "I hope it will send a message."

The terms of the sentence had been worked out in June when Lipscomb pleaded guilty to a single campaign finance violation, admitting to funding half of a $12,500 political poll for City Councilwoman Helen L. Holton. Maryland law prohibits donors from giving more than $4,000 per candidate per election cycle.

The June deal was something of a turning point in the three-year investigation into city government - Lipscomb is the only defendant connected to all of the City Hall corruption cases that have been brought by the state prosecutor.

Prosectors had initially charged Lipscomb with bribing Holton by paying for the poll in exchange for her help shepherding favorable tax credits to his city developments. Holton also was charged with bribery, though the judge dismissed the case against her as well as five of 12 charges against the mayor, saying prosecutors used tainted evidence to secure the indictments.

On the day Lipscomb's bribery trial was set to begin, prosecutors dropped that offense and charged him instead with the lesser campaign finance violation. Prosecutors quickly brought him before a grand jury, using his testimony to shore up their case against Dixon and revive charges against Holton.

Lipscomb likely will be a key witness in the mayor's trial next month. He is one of two developers who donated gift cards to her office when she was City Council president. He is expected to testify that he believed those cards would be given to the city's poor but, according to the indictment filed against her, Dixon used them on herself and her family.

She is accused of perjuring herself by failing to report on her city ethics forms the lavish gifts he gave her.

After the Lipscomb deal was cut, prosecutors also charged baking magnate and mega-developer John Paterakis with campaign finance offenses for funding the other half of the Holton poll. Paterakis pleaded guilty in July and received a sentence similar to Lipscomb's, his frequent partner in Inner Harbor East developments.

At Thursday's sentencing, Lipscomb was accompanied by his two lawyers, but no family or friends. "I apologize to the court," he said, speaking softly with a distinct southern drawl. "I did not bother to see that it [the campaign donation] was done properly."

Gerard P. Martin, Lipscomb's attorney, approached the judge's bench with a cashier's check for $25,000 made out to the Baltimore Director of Finance, showing that his client was ready to pay the fine.

"We don't take that in the courtroom," Sweeney explained.

Sweeney questioned Lipscomb about his community service, which the developer completed before appearing in court.

Lipscomb initially volunteered at Moveable Feast, a nonprofit that provides meals to homebound people who are HIV positive or who have breast cancer, where he was assigned to prepare food. But after 12 hours he stopped.

"I wanted to talk to people and touch people," Lipscomb said. "We didn't get to deliver the food." Calls to Moveable Feast were not returned on Thursday. Martin, Lipscomb's attorney, added that the hours at the nonprofit did not work with Lipscomb's schedule.

Lipscomb transferred to a different volunteer program and spent the rest of his court-ordered community service working at the Academy for Success in West Baltimore, where he said that he wrote grants, set up meetings with influential people and helped "get money to keep the program going." The organization provides after-school activities to the poor, according to its Web site.

"It's been a great personal experience," he said, adding that he plans to continue working with the organization.

Lipscomb attorney Steve Wrobel asked for clarification of those terms, noting that the developer might be compelled to attend groundbreaking ceremonies as part of his job.

"Let me put it this way," Sweeney responded. "I would err on the side of great caution. I would not skate close to the edge. If I even thought there was a question, I would not attend it."

Sweeney allowed Lipscomb to enter probation before judgment, which means his record could be expunged if he completes the terms of his probation. But the judge also had a stern message.

"This is a criminal action that you engaged in, I don't want to paper that over," Sweeney said. "You said that this act was stupid and selfish. The court agrees with that."

The sentencing was the last scheduled court hearing before Baltimore Mayor Sheila Dixon's criminal trial on theft charges, which is set to begin on Nov. 9. No trial has been scheduled for the perjury charges against Dixon. Holton's trial is set for Dec. 9.

The group served by Moveable Feast was misstated in an earlier version of this article. The Baltimore Sun regrets the error.